Microwave-Treated Structural and Network Changes in Filled Industrial EPDM Waste: Effects of Particle Size and Exposure Time
- 1Dokuz Eylul University , , Buca , ,
- 2Standard Profil Ege , , ,
Abstract
Ethylene–propylene–diene monomer (EPDM) compounds used in automotive sealing systems contain permanent cross-links and high amounts of fillers and process oils, which complicate their recycling. This study examined the effects of particle-size fraction (≤125 and ≥125 μm) and microwave exposure time (60–180 s at 600 W) on the structural response of a highly filled industrial EPDM waste. Apparent sol fraction and apparent cross-link density were used as comparative indicators, supported by ATR-FTIR, XPS, TGA, and SEM analyses. The fine fraction treated for 60 s showed the lowest apparent cross-link density (0.72 × 10–4 mol/cm3), corresponding to an apparent reduction of 17.11% relative to untreated ground EPDM. Longer exposure is increasingly favored by network-forming responses, particularly in the coarse fraction, demonstrating competition between network loosening and secondary cross-linking. XPS showed changes in sulfur-containing surface environments, while ATR-FTIR revealed no appreciable shifts in the principal EPDM bands. TGA and SEM showed clear differences between the particle-size fractions. In revulcanized compounds containing 10 phr recycled EPDM, tensile strength remained within 7.71–8.32 MPa, and none of the recycled formulations differed significantly from the reference C-EPDM. Microwave treatment had a significant overall effect on tensile strength (p = 0.014), but only the treated fine fraction differed from its untreated counterpart (p = 0.046); elongation at break did not differ significantly. Surface roughness and Shore A hardness remained broadly comparable. Overall, microwave exposure produced competing particle-size- and time-dependent network responses, indicating a narrow processing window for the controlled modification of highly filled industrial EPDM waste.
Related
- Acetylation of quinoa starch: structural and functional improvements for food and industrial applications
- Frequency‑dependent microwave absorption of crude oil correlated with FTIR‑derived structural indices and asphaltene fraction
- Visible-Light-Driven Photoreduction of Industrial-Grade Graphene Oxide into Single-/Few-Layer Reduced Graphene Oxide Nanosheets: Structural Evolution and Enhanced Electrochemical Energy-Storage Performance
- Evaluation of airborne PFAS concentrations in PFAS-using industrial facilities
- Winery By-Products as Sustainable Functional Resources: An Overview of Composition, Green Extraction Technologies, and Industrial Valorization
BibTeX
@article{uzunbayir2026microwavetreated,
title = {{Microwave-Treated Structural and Network Changes in Filled Industrial EPDM Waste: Effects of Particle Size and Exposure Time}},
author = {Begüm Uzunbayir and Bahadir Uyulgan and Orçun Saf},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c04739},
url = {https://pubs.acs.org/acsodf/article/11/41/62838/5445910/Microwave-Treated-Structural-and-Network-Changes},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Microwave-Treated Structural and Network Changes in Filled Industrial EPDM Waste: Effects of Particle Size and Exposure Time
AU - Begüm Uzunbayir
AU - Bahadir Uyulgan
AU - Orçun Saf
PY - 2026
DA - 2026/10/07
JO - ACS Omega
DO - 10.1021/acsomega.6c04739
UR - https://pubs.acs.org/acsodf/article/11/41/62838/5445910/Microwave-Treated-Structural-and-Network-Changes
AB - Ethylene–propylene–diene monomer (EPDM) compounds used in automotive sealing systems contain permanent cross-links and high amounts of fillers and process oils, which complicate their recycling. This study examined the effects of particle-size fraction (≤125 and ≥125 μm) and microwave exposure time (60–180 s at 600 W) on the structural response of a highly filled industrial EPDM waste. Apparent sol fraction and apparent cross-link density were used as comparative indicators, supported by ATR-FTIR, XPS, TGA, and SEM analyses. The fine fraction treated for 60 s showed the lowest apparent cross-link density (0.72 × 10–4 mol/cm3), corresponding to an apparent reduction of 17.11% relative to untreated ground EPDM. Longer exposure is increasingly favored by network-forming responses, particularly in the coarse fraction, demonstrating competition between network loosening and secondary cross-linking. XPS showed changes in sulfur-containing surface environments, while ATR-FTIR revealed no appreciable shifts in the principal EPDM bands. TGA and SEM showed clear differences between the particle-size fractions. In revulcanized compounds containing 10 phr recycled EPDM, tensile strength remained within 7.71–8.32 MPa, and none of the recycled formulations differed significantly from the reference C-EPDM. Microwave treatment had a significant overall effect on tensile strength (p = 0.014), but only the treated fine fraction differed from its untreated counterpart (p = 0.046); elongation at break did not differ significantly. Surface roughness and Shore A hardness remained broadly comparable. Overall, microwave exposure produced competing particle-size- and time-dependent network responses, indicating a narrow processing window for the controlled modification of highly filled industrial EPDM waste.
SN - 2470-1343
ER -